Cosmic Ray-Modified Astrophysical Shocks: Modeling and Observations

目前宇宙射线（CR）研究的主导范式认为，大部分能量低于千万亿电子伏的银河系CR是通过扩散冲击加速在超新星遗迹（SNR）中产生的。 这现在是一个转折点：很快，理论计算和观测之间的比较，从无线电波段到伽马射线到高能中微子，预计要么确认范式，要么呼吁范式转变。 该项目将开发新的理论和观测技术来测试信噪比范式。 这些理论研究都围绕着一个共同的主题：宇宙射线如何改变冲击波的结构？ 这项工作将研究磁场放大，注入和加速的CRs，尘埃溅射和上游等离子体中的大中性成分的作用。 在所谓的巴尔默主导冲击中对中性氢的分析应该会导致一种新的方法来测量冲击加速效率。 研究将包括考虑宇宙射线如何逃离其加速点并向地球传播以及CR的动力学扩散。 时间和空间依赖的粒子动力学模型将与观测到的非热细丝进行比较，并与高能粒子观测结果相联系，这是一个涉及天体物理学和等离子体物理学的数据分析、理论和计算工作的多学科项目。 与普渡大学计算机图形技术系的学生合作，将与普渡大学的探索学习中心合作，建立一个互动信息亭，向所有访问团体，包括K-12学生，教师和公众解释CR。

The current dominant paradigm in cosmic ray (CR) research says that the bulk of Galactic CRs with energies below a peta-electron volt are created in supernova remnants (SNRs) via diffusive shock acceleration. This is now at a turning point: soon, the comparison between theoretical calculations and observations from the radio band to gamma rays to high energy neutrinos is expected to either confirm the paradigm or call for a paradigm shift. This project will develop novel theoretical and observational techniques to test the SNR paradigm. The theoretical studies are based around a common theme: how do cosmic rays modify the structure of the shock? The work will investigate magnetic field amplification, injection and acceleration of CRs, and the role of dust sputtering and the large neutral component in the upstream plasma. Analysis of neutral hydrogen in the so-called Balmer-dominated shocks should lead to a novel way to measure the shock acceleration efficiency. The research will include consideration of how cosmic rays escape their acceleration sites and propagate towards the Earth and of the kinetic diffusion of CRs. Modeling of time- and spatially-dependent particle dynamics will be compared with observed non-thermal filaments and tied to the results of high energy particle observations.This is a multidisciplinary project involving data analysis and theoretical and computational work in astrophysics and plasma physics. Work with students in the Purdue Computer Graphics Technology Department will lead to an interactive kiosk, in partnership with Purdue's Discovery Learning Center, to explain about CRs to all visiting groups, including K-12 students, teachers, and the general public.